Stretchable and formable lighter than air balloons made from a biaxially oriented polyester film

ABSTRACT

Described are stretchable and formable lighter than air balloons including a high barrier lamination. The stretchable and formable balloons stretch when overinflated instead of failing. The balloons are formed from a lamination including a polyester film with a total thickness of 4 μm to 12 μm including a biaxially oriented polyester core layer and at least one amorphous copolyester skin layer. The polyester film has an Elongation % in the transverse direction (TD) or machine direction (MD) of greater than 125%.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. Ser. No.12/202,655, filed Sep. 2, 2008, now U.S. Pat. No. 8,399,080, issued Mar.19, 2013, which is a continuation-in-part of U.S. Ser. No. 11/651,103,filed Jan. 9, 2007, now U.S. Pat. No. 7,799,399, issued Sep. 21, 2010,which claims the benefit of U.S. Provisional Application Ser. No.60/811,410 filed Jun. 7, 2006, the entirety of which each application isincorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to stretchable and formable lighter than airballoons including a high barrier lamination. The stretchable andformable balloons stretch when overinflated instead of failing.

BACKGROUND OF THE INVENTION

Lighter than air balloons may be formed from thin plastic films thatinclude a gas barrier layer. Compared with conventional latex balloons,such films may reduce diffusion of lighter than air gases like helium,the gas typically used for inflating balloons, and give the balloons amore attractive appearance like a Valentine's Day heart shape, flowershapes, animal shapes, any famous character printing thereon and so on.

U.S. Pat. No. 4,077,588, the disclosure of which is totally incorporatedby reference herein, describes in the Abstract thereof, a substantiallypermanently buoyant balloon suitable for use as a toy or in advertising.For example, a balloon is provided which includes an envelope containinga lighter than air gas such as helium. The envelope is made fromattached panels of a non-elastomeric polymer sheet material carrying acontinuous metal layer on at least one side thereof. The metal layer caneither be a thin metal film contiguously bonded to the polymer, or canbe metal which is vapor deposited over the surface of the polymer. Theballoon itself is constructed so that the ratio of its volume taken tothe two-thirds power divided by its surface area is in the range of fromabout 0.21 to about 0.01, and the weight of the envelope can range fromabout 2.6×10⁻⁴ gm/cm² to about 1.7×10⁻² gm/cm². The envelope ispreferably manufactured in a two dimensional “lay-flat” form in anydesired two dimensional shape, unlike conventional balloon envelopeswhich are inherently three dimensional surfaces. Balloon envelopeshaving the above described volume to surface area ratio and made withthe above described composite panel material will be maintained buoyantfor an indefinite period of time when filled with the lighter than airgas.

U.S. Pat. No. 5,338,243, the disclosure of which is totally incorporatedby reference herein, describes in the Abstract thereof, a balloonproduct, including at least two sheets, having a background depiction onone sheet and a foreground depiction on the other. The foregrounddepiction has a complementary relationship to the background depictionso as to provide a three-dimensional animated image.

U.S. Pat. No. 5,713,777, the disclosure of which is totally incorporatedby reference herein, describes in the Abstract thereof, a non-latexinflatable toy in the form of a hand puppet. The puppet includes threesheets defining an inflatable chamber and a pocket for the hand of theuser.

The appropriate components and process aspects of each of the foregoingU.S. patents may be selected for the present disclosure in embodimentsthereof.

Although there have been attempts to improve the barrier properties oforiented polyester films in order to improve the lifetime of theballoons, there are other factors that also contribute to the lifetimeof the balloons. More specifically, the leakage of helium gas occurs notonly through the gas barrier film surface, but also through the sealingarea where the two sheets are enveloped, especially when the balloon isfully inflated. The reason for this weak sealing of the orientedpolyester film is that the surface of the oriented film is highlycrystallized and shows poor sealing strength with the sealing layer.Another disadvantage of the oriented polyester film is that pooradhesion with the gas barrier layer occurs due to the same reason.

Further, the processes of the balloon fabrication are severe, involvingabrasion and wet coating, which can reduce the effectiveness of the gasbarrier layer by damaging and/or removing this layer. The gas barrier ofthe processed balloon should not be significantly degraded compared tothe unprocessed substrate used. Furthermore, the balloon will be exposedto unexpected handling during the market use, folded, smashed, etc.under various climate conditions.

SUMMARY OF THE INVENTION

Described are lighter than air balloons including a high barrierlamination. The lamination may include a co-extruded and biaxiallyoriented polyester film. The polyester film may have an Elongation % inthe transverse and/or machine direction of greater than 125%.

One embodiment is a long life balloon formed from a lamination. Thelamination includes a polyester film with a total thickness of 4 μm to12 μm. The polyester film includes a biaxially oriented polyester corelayer and at least one amorphous copolyester skin layer. The laminationalso includes a sealant layer and a gas barrier layer on an oppositeside of the polyester film from the sealant layer. The oxygentransmission rate of the balloon is less than 0.1 cc/100 sqin/day, abonding strength of the gas barrier layer to the surface of thepolyester film is more than 300 g/in at dry conditions, a sealingstrength of the balloon is more than 3.5 kg/in, and a floating time ofthe balloon is more than 20 days.

The sealant layer may include a low density polyethylene. The laminationmay include an anchor layer between the sealant layer and the amorphouscopolyester skin layer. The lamination may include a primer layerbetween the biaxially oriented core layer and the gas barrier layer. Thebiaxially oriented core layer may be co-extruded with the amorphouscopolyester skin layer.

The amorphous copolyester skin layer may have a melting point of lessthan 210° C. and the amorphous copolyester skin layer may contain noadded particles. The dry bonding strength of the gas barrier layer maybe more than 600 g/in. The floating time of the balloon may be more thanabout 30 days.

Another embodiment of a balloon formed from a lamination includes alamination including a polyester film with a total thickness of 4 μm to12 μm and including a biaxially oriented polyester core layer and atleast one amorphous copolyester skin layer. The lamination may alsoinclude a sealant layer adjacent to the amorphous copolyester skinlayer, a first gas barrier layer on an opposite side of the polyesterfilm from the sealant layer, and a second gas barrier layer on the firstgas barrier layer. An oxygen transmission rate of the balloon may beless than 0.02 cc/100 sqin/day, a sealing strength of the balloon may bemore than 3.5 kg/in, and a floating time of the balloon may be more than40 days.

The first or second gas barrier layer may be a metal or ceramic layer.The first or second gas barrier layer may include a polymer, such as forexample an ethylene-vinyl alcohol polymer, a poly vinyl alcohol polymer,or a poly vinyl amine copolymer. The gas barrier including the polymermay further include at least one cross-linker. The sealant layer mayinclude a low density polyethylene.

The balloon may further include an anchor layer between the sealantlayer and the amorphous copolyester skin layer. The first gas barrierlayer may be on a surface of the biaxially oriented core layer. Theballoon may include a primer layer between the biaxially oriented corelayer and the first gas barrier layer. The biaxially oriented core layermay be co-extruded with the amorphous copolyester skin layer. Thefloating time of the balloon may be more than about 50 days.

Yet another embodiment of a balloon formed from a lamination includes alamination including a polyester film with a total thickness of 4 μm to12 μm including a biaxially oriented polyester core layer and at leastone amorphous copolyester skin layer, a sealant layer adjacent to theamorphous copolyester skin layer, and a ceramic gas barrier layer on anopposite side of the polyester film from the sealant layer. The oxygentransmission rate of the balloon may be less than 0.1 cc/100 sqin/day, asealing strength of the balloon may be more than 3.5 kg/in, a totallight transmittance of the lamination may be more than 30% and afloating time of the balloon may be more than 20 days.

The sealant layer may include a low density polyethylene. The ceramicgas barrier layer may include AlOx or SiOx. The balloon may include ananchor layer between the sealant layer and the amorphous copolyesterskin layer, and a primer layer between the biaxially oriented core layerand the ceramic gas barrier layer. The biaxially oriented core layer maybe co-extruded with the amorphous copolyester skin layer.

The haze of the lamination may be less than 90%. The balloon may furtherinclude a second gas harrier layer on a ceramic gas barrier layer. Thesecond gas barrier layer may include a polymer, such as ethylene-vinylalcohol polymer, a poly vinyl alcohol polymer, or a poly vinyl aminecopolymer. The second gas barrier layer may further include at least onecross-linker. The floating time of the balloon may be more than 30 days.

Another embodiment of a balloon formed from a lamination includes alamination including a polyester film with a total thickness of 4 μm to12 μm comprising a biaxially oriented polyester core layer and at leastone amorphous copolyester skin layer. The polyester film has anElongation % in the transverse direction (TD) and/or machine direction(MD) of greater than 125%.

The polyester film may have a tensile strength of 30-40 KPsi in the TDand/or MD direction, an may have a Young's Modulus of 420-480 KPsi inthe TD and/or MD direction.

The lamination may further include a sealant layer adjacent to theamorphous copolyester skin layer, and a gas barrier layer on an oppositeside of the polyester film from the sealant layer, wherein an oxygentransmission rate of the balloon is less than 0.1 cc/100 sqin/day, a drybonding strength of the gas barrier layer to the surface of thepolyester film is more than 300 g/in, a sealing strength of the balloonis more than 3.5 kg/in, and a floating time of the balloon is more than20 days.

The gas barrier layer may be a metal or ceramic layer. The sealant layermay include a low density polyethylene. The lamination may furtherinclude an anchor layer between the sealant layer and the amorphouscopolyester skin layer. The lamination may further include a primerlayer between the biaxially oriented core layer and the gas barrierlayer. The core layer may be co-extruded with the amorphous copolyesterskin layer.

The amorphous copolyester skin layer may have a melting point of lessthan 210° C. The amorphous copolyester skin layer may contain no addedparticles. The dry bonding strength of the gas barrier layer may be morethan 600 g/in.

Embodiments of a method of forming a formable balloon includes placing aballoon in a mold, wherein the balloon is formed from a lamination andthe lamination includes a polyester film including a biaxially orientedpolyester core layer and at least one amorphous copolyester skin layer,the polyester film has a total thickness of 4 μm to 12 μm, and thepolyester film has an Elongation % in the transverse direction (TD) ormachine direction (MD) of greater than 125%, and inflating the balloonin the mold to form the balloon to the shape of the mold.

Embodiments of a deformable balloon formed from a lamination include alamination including a polyester film with a total thickness of 4 μm to12 μm comprising a biaxially oriented polyester core layer and at leastone amorphous copolyester skin layer. The polyester film has anElongation % in the transverse direction (TD) or machine direction (MD)of greater than 125%, and the balloon has a higher elongation and lowertensile strength in the TD or MD direction.

Embodiments of a method of forming a balloon from a lamination includesco-extruding a polyester film including a polyester core layer includingcrystalline polyester and at least one amorphous copolyester skin layer,and biaxially orienting the core layer under conditions such that thepolyester film has an Elongation % in the transverse direction (TD) ormachine direction (MD) of greater than 125%.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a film in accordance with onepossible embodiment of the present disclosure.

FIG. 2 illustrates an example of a multi-layer oriented polyester film(A) used as part of a lamination in accordance with an embodiment of thepresent disclosure.

FIG. 3 illustrates an example of a lamination that includes a primerlayer (D) and an anchor layer (E) in accordance with an embodiment ofthe present disclosure.

FIG. 4 illustrates an embodiment in which a polymeric gas barrier layer(D) is formed between a metallized or ceramic gas barrier layer (C) andthe polyester film (A) in accordance with an embodiment of the presentdisclosure.

FIG. 5 illustrates an embodiment in which a polymeric gas barrier layer(D) is formed on top of a metallized or ceramic gas barrier layer (C) inaccordance with an embodiment of the present disclosure.

FIG. 6 is a graph of Elongation % v. Machine Direction Stretching (MDS)Temperature for a multi-layer oriented polyester film including a corelayer of crystalline polyester.

FIG. 7 is a graph of Elongation % v. Total MDS Draw for a multi-layeroriented polyester film including a core layer of crystalline polyester.

FIG. 8 is a graph of Tensile Strength v. MDS Temperature for amulti-layer oriented polyester film including a core layer ofcrystalline polyester.

FIG. 9 is a graph of Tensile Strength v. Total MDS Draw for amulti-layer oriented polyester film including a core layer ofcrystalline polyester.

FIG. 10 is a graph of Young's Modulus v. MDS Temperature for amulti-layer oriented polyester film including a core layer ofcrystalline polyester.

FIG. 11 is a graph of Young's Modulus v. Total MDS Draw for amulti-layer oriented polyester film including a core layer ofcrystalline polyester.

DETAILED DESCRIPTION OF THE INVENTION

Described are long life balloons formed from a lamination. Thelamination may include a polyester film that includes a biaxiallyoriented polyester core layer and an amorphous copolyester skin layer.The lamination may also include a sealant layer and a gas barrier layeron an opposite side of the polyester film from the sealant layer.

The balloons may have an oxygen transmission rate of less than 0.1cc/100 sqin/day, a bonding strength of the gas barrier layer to thesurface of the polyester film of more than 300 Win at dry conditions, asealing strength of the balloon of more than 3.5 kg/in, and a floatingtime of the balloon is more than 20 days.

In embodiments, a film material for the balloon may include a thin,extensible, yet stress crack resistant film material including two ormore layers. The film may be prepared on, for example, a commercialbiaxially orientation tentering film line.

An embodiment shown in FIG. 1 includes a film 10 including a first highcrystalline polyester layer 12 and a second amorphous copolyester layer14. Preferably, the thickness of film 10 including layers 12 and 14 is4-12 μm, or 6-9 μm. The structure in FIG. 1 also includes a linear lowdensity polyethylene (LLDPE) layer 20.

The high crystalline polyester layer 12 can include any suitablematerial. For example, in embodiments, high crystalline polyester layer12 includes high intrinsic viscosity (IV) homopolyesters or copolyesterof PET/PBT, an intrinsic viscosity (IV) >0.50 or an IV of >0.60.

Crystallinity is defined as the weight fraction of material producing acrystalline exotherm when measured using a differential scanningcalorimeter. For high crystalline polyester, an exothermic peak in themelt range of 220° C. to 290° C. is most often observed. Highcrystallinity is therefore defined as the ratio of the heat capacity ofmaterial melting in the range of 220° C. to 290° C. versus the totalpotential heat capacity for the entire material present if it were allto melt. A crystallinity value of >35% weight fraction is consideredhigh crystallinity. The amorphous copolyester layer 14 can include anysuitable material. For example, in embodiments, amorphous copolyesterlayer 14 includes isophthalate modified copolyesters, sebacic acidmodified copolyesters, diethyleneglycol modified copolyesters,triethyleneglycolmodified copolyesters, cyclohexanedimethanol modifiedcopolyesters. A metallized barrier layer 16 may be disposed over all ora part of the high crystalline layer 12. Deposition of the barrier layermay be done via a low pressure vacuum metallizing process of a metalsuch as aluminum, or ceramic such as AlOx, SiOx. In embodiments, thefilm may be processed into any desired configuration. For example,printing 18 may be disposed upon a metallized layer 16.

FIG. 2 shows an example of a multi-layer oriented polyester film (A)used as part of a lamination. The oriented polyester film (A) mayinclude at least two layers, a core layer (a) and at least one skinlayer (b).

The core layer (a) may be a high crystalline polyester film achieved bybi-axial orientation. This crystallized portion of the film maycontribute to making the film stiff and tear resistant during theballoon fabrication process, while remaining thin enough to make theballoon light.

The polyester of the core layer (a) may be a polymer obtained bypolycondensation of a diol and a dicarboxylic acid. The dicarboxylicacids may include, for example, terephthalic acid, isophthalic acid,phthalic acid, naphthalenedicarboxylic acid, adipic acid and sebacicacid, and the diols may include, for example, ethylene glycol,trimethylene glycol, tetramethylene glycol and cyclohexane dimethanol.

The polyesters may include, for example, polymethylene terephthalate,polyethylene terephthalate, polypropylene terephthalate, polyethyleneisophthalate, polytetramethylene terephthalate,polyethylene-p-oxybenzoate, poly-1,4-cyclohexylenedimethyleneterephthalate and polyethylene-2,6-naphthalate.

These polyesters may be homopolymers and copolymers, and the co-monomersmay include, for example, diols such as diethylene glycol, neopentylglycol and polyalkylene glycols, dicarboxylic acids such as adipic acid,sebacic acid, phthalic acid, isophthalic acid and2,6-naphthalenedicarboxylic acid, and hydroxycarboxylic acids such ashydroxybenzoic acid and 6-hydroxy-2-naphthoic acid.

Polyethylene terephthalate, and polyethylene naphthalate(polyethylene-2,6-naphthalate) may be used to achieve highercrystallinity. Further, the polyester may include various types ofadditives, for example, an antioxidant, a heat-resistant stabilizer, aweather-resistant stabilizer, an ultraviolet ray absorber, an organicslipperiness imparting agent, a pigment, a dye, organic or inorganicfine particles, a filler, an antistatic agent, a nucleating agent andthe like.

One or more skin layer(s) may be co-extruded with the core layer (a) toincrease the bonding between the core layer and the skin layer(s). FIG.2, shows a skin layer (b) adjacent to heat sealant layer (B). The skinlayer (b) adjacent to the heat sealant layer (B) may include anamorphous polyester to increase the bonding between the skin layer (b)and the heat sealant layer (B).

The melting point of the skin layer (b) adjacent to the heat sealantlayer (B) may be 210° C. or less. If the melting point of the skin layer(b) is much higher than 210° C., the amorphous layer may not melt wellduring a heat set process of the biaxially oriented film. This couldcause low sealing strength during the heat sealing process used tofabricate the film into a balloon.

The copolyester for this skin layer (b) may be a copolyester made frompolycondensation of diols and dicarboxylic acids described above. Theskin layer (b) is kept amorphous during and after the film makingprocess. A preferred polyester for the amorphous layer is a copolyesterof isophthalate. The mol % of the isophthalate may be higher than 10 mol%, or more than 15 mol %.

The thickness of skin layer (b) may be 0.2 μm to 1.5 μm, morepreferably, 0.3 μm to 0.7 μm. If the skin layer (b) is thinner than 0.2μm, sufficient sealing strength may not been obtained. If skin layer (b)is thicker than 1.5 μm, the polyester film (A) may not be stiff enoughto support the balloon structure and the film may be difficult tohandle.

The leakage of the helium gas occurs not only through the gas barrierfilm surface, but also through the sealing area where the two sheets areenveloped, especially when the balloon is fully inflated. Accordingly,the sealing strength of the sealant layer after balloon fabrication maybe more than about 3.5 kgf/in, or more than about 4 kgf/in, to preventleakage of helium gas through the heat sealed portion.

The skin layer (b) adjacent to the heat sealant layer (B) may notinclude any added particles. Such particles may be used to make the filmslippery and improve handling. However, such particles would enhance thecrystallinity of the amorphous layer, which could decrease the sealingstrength between the heat sealant layer (B). These particles may alsocreate bumps on the surface of the gas barrier layer when the film iswound on a roll.

In the method of producing the polyester film (A) of the presentinvention, melted polymers for the core layer (a) and the skin layer (b)may be co-extruded and laminated on a cooling drum and solidified toform a sheet. The sheet-shaped molding is preferably stretched 2 to 5times in the longitudinal direction and 2 to 5 times in the transversedirection, and then heat-set at a temperature of 220 to 250° C.

In embodiments, the total thickness of the polyester film (A) may be 4μm to 12 μm, preferably, 6 to 9 μm. If the film is thicker than 12 μm,the unit weight of the balloon may become too great to achieve thetargeted floatation time at higher elevations where air density islower. If the film is thinner than 4 μm, the film may not be robustenough to survive the severe processes of balloon fabrication, causingwrinkles, folding and web breaks.

Recycled pellets made from the polyester film (A) may also be usable.

FIG. 3 shows an embodiment of a lamination that includes a primer layer(D) and an anchor layer (E). Primer layer (D) may be applied between thepolyester film (A) and the gas barrier layer (C), to increase thebonding between them and to prevent damage or removal. Similarly, theanchor layer (E) may be used to increase bonding between the polyesterfilm (a) and sealant layer (B).

At least one anchor layer (E) may be applied before the sealant layer(B) is laminated on the polyester film (A). The anchor layer (E) may beselected from, but not limited to, a polyethylene dispersion,particularly polyethylenimine.

Anchor layer (E) may be applied in a dispersion in water or anothersolvent, using an application method such as gravure coating, meyer rodcoating, slot die, knife over roll, or any variation of roll coating.The applied dispersion may then be dried with hot air, leaving a layerapproximately 0.01 to 0.1 μm thick. The skin layer (b) may be treatedprior to application of the anchor layer (E). The treatment is used toincrease the surface energy of the skin layer (b) to increase wetting ofthe dispersion and bond strength of the dried anchor layer (E).Treatment methods include corona, gas modified corona, atmosphericplasma, and flame treatment.

Sealant layer (B) may be hot melt extruded as a coating onto the anchorlayer (E). The sealant layer (B) may be a grade of Low DensityPolyetheylene, or a blend of Low Density Polyethylene and Linear LowDensity Polyethylene. The temperature of the melt may be from 305 to325° C., with a higher temperature being preferable for melting of theskin layer (b). The melt layer may then be chilled to form sealant layer(B) with a thickness of from 10 to 20 μm.

Another method for applying the sealant layer (B) is to use an adhesiveto laminate a pre-formed Low Density Polyethylene sheet to the skinlayer (b). Suitable adhesives include, but are not limited to,polyester, polyester urethane, polyether urethane, and acrylicchemistries. Adhesive thickness may be from 1 to 6 μm thick. Thethickness of a pre-formed low density polyethylene sealant sheet mayrange from 10 to 100 μm, preferably using a thinner sealant sheet from10-30 μm for smaller volume balloons, and less than 11 liters, tomaintain buoyancy in air.

The gas barrier of the film is one of the factors in maintaining thelong life of a balloon. At least one gas barrier layer (C) may beapplied on the surface of the polyester film (A) to make the oxygentransmission rate of the balloon less than 0.1 cc/100 sqin/day. The gasbarrier layers may be a metallized layer such as Al, or a ceramicdeposition layer such as SiOx and AlOx.

The metallizing gas barrier layer/ceramic deposition layer may beapplied using any available deposition method such as physical vapordeposition, or chemical vapor deposition. The most common method isphysical vapor deposition of an Al layer in a vacuum, in which aluminumis heated in absolute pressure preferably less than 1.0×10⁻³ mbar. Thelow pressure allows aluminum to form a vapor at a considerably lowertemperature so that it can be applied without thermal damage to thefilm. The aluminum can be in the form of a wire that is fed to thesurface of an electrically heated plate known as a boat. Or the aluminumcan be in the form of an ingot that is heated within a crucible. Thealuminum vapor is condensed on the film surface in an open span or withthe film against a chill roll to dissipate the heat of the vapor. Thecondensed aluminum vapor forms grains of solid aluminum with a totalthickness of 50 to 1000 angstroms. Preferably, the thickness of thealuminum layer is between 300 to 500 angstroms. A thin aluminum layermay not provide a very high gas barrier, and thick layers are difficultand inefficient to apply, and in practice provide diminishingperformance vs. additional thickness.

Adhesion between the gas barrier layer (C) and the polyester layer (A)may be also a factor in increasing the lifetime of a balloon formed froma lamination because damage or removal of the gas barrier layer duringthe severe processes of balloon fabrication and un-expected handling bythe end consumers degrades the barrier property of the film.

The bonding strength between the polyester film (A) and the gas barrierlayer (C) may be more than 300 g/in, preferably more than 600 g/in. Toachieve such bond strength values, an electrical treatment such asplasma/corona treatment on the polyester film (A) may be used before thegas barrier layer is applied on the polyester film (A). Since the filmmay be exposed to wet processes during the balloon fabrication and wetclimates during the consumer's usage, the bonding strength between thepolyester film (A) and the gas barrier layer (C) in wet conditions ispreferably more than 30 g/in, more preferably more than 50 g/in. Toachieve such high dry and wet bond strength values, an additionaldeposition anchorage layer, such as Cu seeding, Ni seeding may beapplied before the main metal/ceramic barrier layer is deposited. Inaddition, the additional primer layer (D) may be applied between thepolyester film (A) and the gas barrier layer (C), increasing the bondingbetween them and preventing the damage or removal of the barrier layer(C).

The primer layer (D) may be a polymeric binder that adheres well withboth the polyester film (A) and the gas barrier layer. Examples of suchpolymers may include, but are not limited to, polyester, acrylic,polyurethane and their mixture or co-polymer.

The polyester for the additional primer layer (D) may be selected frompolyester resin copolymerized with a compound having a carboxylic acidbase. Examples of compounds having a carboxylic acid base include, forexample, trimellitic acid, trimelliticanhydride, pyromellitic acid,pyromellitic anhydride, 4-methylcyclohexene-1,2,3-tricarboxylic acid,trimeric acid, 1,2,3,4-butane tetracarboxylic acid, 1,2,3,4-pentanetetracarboxylic acid, 3,3′,4,4′-benzophenone tetracarbxylic acid,5-(2,5-dioxotetrahydrofurfuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylicacid, 5-(2,5-dioxotetrahydrofurfuryl)-3-cyclohexene-1,2-dicarboxylicacid, cyclopentane tetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalene tetracarboxylic acid, ethyleneglycol bistrimellitate, 2,2′,3,3′-diphenyl tetracarboxylic acid,thiophene-2,3,4,5-tetracarboxylic acid, ethylene tetracarboxylic acidand the like, or alkali metal salts, alkali earth metal salts andammonium salts thereof can be used; however, the present invention isnot limited to these compounds.

As diol components of the polyester resins (A) and (B) ethylene glycol,diethylene glycol, polyethylene glycol, propylene glycol, polypropyleneglycol, 1,3-propane diol, 1,3-butanediol, 1,4-butanediol,1,5-pentanediol, 1,6-hexane diol, 1,7-heptane diol, 1,8-octane diol,1,9-nonane diol, 1,10-decane diol, 2,4-dimethyl-2-ethylhexane-1,3-diol,neopentylglycol, 2-ethyl-2-butyl-1,3-propane diol,2-ethyl-2-isobutyl-1,3-propane diol, 3-methyl-1,5-pentane diol,2,2,4-trimethyl-1,6-hexane diol, 1,2-cyclohexane dimethanol,1,3-cyclohexane dimethanol, 1,4-cyclohexane dimethanol,2,2,4,4-tetramethyl-1,3-cyclobutane diol, 4,4′-thiodiphenol, bisphenolA, 4,4′-methylene diphenol, 4,4′-(2-norbornylidene)diphenol,4,4′-dihydroxybiphenol, o-, m- and p-dihydroxybenzene,4,4′-isopropylidene phenol, 4,4′-isopropylidene bindiol,cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol,bisphenol A and the like can be used.

The acrylic resin for the additional primer layer (D) may be selectedfrom resins such as a monomer component which constitutes the acrylicresin, for example, an alkyl acrylate, an alkyl methacrylate, (examplesof such alkyl groups include a methyl group, an ethyl group, an n-propylgroup, an isopropyl group, an n-butyl group, an isobutyl group, at-butyl group, a 2-ethylhexyl group, a lauryl group, a stearyl group, acyclohexyl group, a phenyl group, a benzyl group, a phenylethyl groupand the like), a monomer having a hydroxyl group such as 2-hydroxyethylacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate,2-hydroxypropyl methacrylate or the like, a monomer having an amidegroup such as acrylamide, methacrylamide, N-methyl acrylamide, N-methylmethacrylamide, N-methylol acrylamide, N-methylol methacrylamide,N,N-dimethylol acrylamide, N-methoxymethyl acrylamide,N-methoxymethylmethacrylamide, N-phenyl acrylamide or the like, amonomer having an amino group such as N,N-diethylamino ethyl acrylate,N,N-diethylamino ethyl methacrylate or the like, a monomer having anepoxy group such as glycidyl acrylate, glycidyl methacrylate or thelike, a monomer having a carboxylic acid or a salt thereof such asacrylic acid, methacrylic acid or a salt thereof (an alkali metal salt,an alkali earth metal salt, an ammonium salt or the like) and the likewhereupon one or more types of these monomer components arecopolymerized.

In addition to the binder, a proper cross-linker may reinforce thebonding. Examples of the cross-linker include a melamine-basedcross-linker, epoxy-based cross-linker, aziridine-based cross-linker,epoxyamide compounds, titanate-based coupling agents, e.g., titaniumchelate, oxazoline-based cross-linker, isocyanate-based cross-linker,methylolurea or alkylolurea-based cross-linkers, and acrylamide-basedcross-linkers.

The primer layer (D) may be applied in a dispersion or solution of wateror another solvent, using an application method such as gravure coating,meyer rod coating, slot die, knife over roll, or any variation of rollcoating. The in-line coating method, applying the primer layer in theprocess of polyester film (A), is preferred. The primer dispersion orsolution may be applied right after the elongation step in thelongitudinal direction, then dried in an oven following the elongationstep in the transverse direction. The thickness of the primer layer (B)may be between 10 nm to 200 nm, more preferably, 20 nm to 100 nm toobtain preferable adhesiveness and gas barrier properties.

These layers and processes can be used to produce a balloon that showsextra long life, floats consistently, and maintains its shape for salemore than about 20 days, preferably more than about 30 days after beingproperly filled with helium gas.

In order to further improve the lifetime of a balloon, a lamination thatincludes two or more gas barrier layers can be produced. For example,one of the gas barrier layers can be a metallized or ceramic layer andthe other can be a polymer gas barrier layer.

FIGS. 4 and 5 illustrate embodiments that include two gas barrierlayers. FIG. 4 illustrates an embodiment in which a polymeric gasbarrier layer (D) is formed between a metallized or ceramic gas barrierlayer (C) and the polyester film (A). FIG. 5 illustrates an embodimentin which a polymeric gas barrier layer (D) is formed on top of ametallized or ceramic gas barrier layer (C). The laminate in FIG. 5 alsoincludes an anchor layer (E) between the skin layer (b) of polyesterfilm (A) and sealant layer (B).

The combination of the metallized layer/ceramic deposition layer and thepolymeric layer creates a very high gas barrier property that canfurther improve the lifetime of a balloon. In addition to improving thegas barrier characteristics of the laminate, a gas barrier layer (D) canalso prevent damage or removal of the gas barrier layer (C) during thesevere processes of balloon fabrication and during handling by the endconsumer. The polymeric barrier layer (D) may be softer than themetal/ceramic barrier layer (C) and is able to maintain a good barrieras the secondary barrier layer after processing and handling.

The gas barrier layer (D) can exist anywhere in the laminate,preferably, between the gas barrier layer (C) and the surface of thepolyester film (A) or on the top of the gas barrier layer (C). Thepolymeric gas barrier layer can include ethylene-vinyl alcohol (EVOH),poly vinyl alcohol (PVOH), poly vinyl amine, and their mixture orco-polymer.

In addition, a proper cross-linker can be added to reinforce the layer.Examples of cross-linkers include melamine-based cross-linkers,epoxy-based cross-linkers, aziridine-based cross-linkers, epoxyamidecompounds, titanate-based coupling agents, e.g., titanium chelate,oxazoline-based cross-linkers, isocyanate-based cross-linkers,methylolurea or alkylolurea-based cross-linkers, aldehyde-basedcross-linkers and acrylamide-based.

The polymeric gas barrier layer (D) may be applied in a dispersion orsolution in water or another solvent, using an application method suchas gravure coating, meyer rod coating, slot die, knife over roll, or anyvariation of roll coating. The applied dispersion or solution may thenbe dried with hot air. The surface may be treated prior to applicationof the polymeric gas barrier layer.

The polymeric coating formulation may be selected to enable solutions tobe in-line coated, stretched in the transverse orientation processwithout attendant and cracking problems, and to provide excellent gasbarrier properties. For example, a higher content of hydroxyl groups inthe polymers may provide increased water solubility and better barrierproperties. Such polymers, however, may cause cracking in the layer upontransverse direction orientation, which may ultimately degrade thebarrier property.

A lamination including the polymeric gas barrier layer may have an O2TRof less than 0.02 cc/100 sqin/day, preferably less than 0.01 cc/100sqin/day. Accordingly, a balloon including such a lamination can possessextra long life, float consistently for more than about 40 days, andmaintain its shape for sale, preferably more than about 50 days afterproper filling with helium gas.

Once the laminations are prepared, the following process may be used tofabricate the balloons: 1) flexographic printing of graphic designs onthe opposite surface of the sealant, 2) slitting of the subsequentprinted web, 3) fabrication of the balloons by die-cutting and a heatsealing process, and 4) folding and packaging of the finished balloons.

Flexographic printing may be used to print graphic designs on theballoons. The printing equipment used in this process may be set up in amanner that will prevent scratching, scuffing, or abrading the gasbarrier surface. The opposite side of the sealant layer of the laminatemay be printed on the metal surface with up to 10 colors of ink, using aflexographic printing press. Each color receives some drying prior toapplication of the subsequent color. After print application, the inksmay be fully dried in a roller convective oven to remove all solventsfrom the ink.

Slitting may be accomplished in any suitable fashion. The slittingequipment used in this process is desirably set up in a manner that willprevent scratching, scuffing, or abrading the gas barrier surface. Inone embodiment, the printed web may be cut to lengths adequate for theballoon fabrication process by rewinding on a center drivenrewinder/slitter using lay-on nip rolls to control air entrapment of therewound roll.

Balloon fabrication may be accomplished in any suitable fashion. Thefabrication equipment used in this process is desirably set up in amanner that will prevent scratching, scuffing, or abrading the gasbarrier surface. The slit webs may be fabricated into balloons byaligning two or more webs into position so that the printed graphics areproperly registered to each other, then are adhered to each other andcut into shapes using known methods. A seam thickness of 1/64″ to ½″ maybe used, as this seam thickness has been found to have greaterresistance to defects with an optimal seam being 1/16″ to ⅛″.Optionally, a valve can be inserted into an opening and the layersabutting the valve adhered to form a complete structure.

Folding may be accomplished in any suitable fashion. The foldingequipment used in this process is desirably set up in a manner that willprevent scratching, scuffing, or abrading the gas barrier surface. Thefabricated balloons may be mechanically folded along multiple axes usingmany different mechanical processes or by hand. The balloon can befolded to the proper size mechanically and then mechanically or by handloaded into a pouch. The balloon can also be hand folded along multipleaxes with care taken not to scratch, scuff or abrade the metalizedsurface. The hand folded balloon can also be inserted into a pouch byhand or mechanically.

Stretchable and Formable Balloons

Polyester based balloons will typically fail when inflated beyond theirphysical capacity. However, it was discovered that polyester balloonswith stretchability and formability characteristics may be created. Thestretchable and formable balloons stretch when overinflated instead offailing.

In some embodiments, a balloon with increased elasticity and formabilitycan be produced by decreasing the orientation of the core layer in amulti-layer oriented polyester film (A) including a core layer (a) ofcrystalline polyester. By decreasing the orientation of the core layer,film elongation before break can be increased. This allows the balloonto be stretched beyond its normal physical dimension while stillmaintaining adequate float properties—as opposed to bursting, which mayoccur in other designs with typical orientation of the core layer. Whilethe tensile strength properties are decreased by reducing theorientation of the core layer, it was surprisingly found that thetensile properties are reduced to allow stretching, but are stillsufficient. Film elongation may be increased in the machine direction,the transverse direction or both depending upon the desired results.

Reduction in film orientation may be achieved in a variety of waysincluding changing the temperature at which the film is stretched, therate at which the film is stretched, or the overall amount that the filmis stretched.

The elastic and formability characteristics may be used to facilitatespecialty design balloons where elongation and distortion are desired.For example, the balloon may be designed to have higher elongation/lowertensile in the TD or MD direction. Some embodiments of a balloon withincreased elastic characteristics may be a formable balloon. Theformable balloon can be inflated in a mold allowing it to take the shapeof the mold. In this manner, balloons of a variety of desirable shapesmay be achieved.

In some embodiments, larger balloons can be produced on the sameequipment as typically sized balloons by intentionally expanding aballoon of a typical size to a specified percentage beyond its normalcapacity. In this case, physical properties could be manipulated to havehigher elongation/lower tensile in both the TD and MD directions(balanced). In addition or alternatively, a balloon that is smaller thana typical balloon before inflation but expands to typical balloon sizeor larger may be created. For example, improved balloon MSI (millionssquare inch) yield can be achieved by starting with a smaller balloontemplate, and then stretching the balloon until it reaches the original.In addition, general yield can be improved since balloons are lesslikely to burst and will instead stretch and give when over inflated.

In some embodiments of a multi-layer oriented polyester film that may beused for an elastic or formable balloon, the multi-layer orientedpolyester film has an Elongation (%) in the TD and/or MD direction ofgreater than 125%, greater than 130%, or greater than 135%. In someembodiments, the Elongation (%) in the TD and/or MD direction is between125%-165%, between 130%-150%, or between 135%-145%.

In some embodiments of a multi-layer oriented polyester film that may beused for an elastic or formable balloon, the multi-layer orientedpolyester film has a tensile strength in the TD and/or MD direction ofless than or equal to 40 Kpsi, of less than or equal to 38 Kpsi, or ofless than or equal to 35 Kpsi. In some embodiments of a multi-layeroriented polyester film that may be used for an elastic or formableballoon, the multi-layer oriented polyester film has a tensile strengthin the TD and/or MD direction of greater than or equal to 30 Kpsi, ofgreater than or equal to 32 Kpsi, or of greater than or equal to 33Kpsi. In some embodiments, preferable ranges for tensile strength arebetween 30-40 Kpsi, between 32-38 Kpsi, and between 33-35 Kpsi. If thetensile strength is too high, the film may not allow sufficientstretching prior to breaking. If the tensile strength is too low, thefilm may not have sufficient strength for balloon purposes.

In some embodiments of a multi-layer oriented polyester film that may beused for an elastic or formable balloon, the multi-layer orientedpolyester film has a Young's Modulus in the TD and/or MD direction ofless than or equal to 480 Kpsi, of less than or equal to 465 Kpsi, or ofless than or equal to 455 Kpsi. In some embodiments of a multi-layeroriented polyester film that may be used for an elastic or formableballoon, the multi-layer oriented polyester film has a Young's Modulusin the TD and/or MD direction of greater than or equal to 420 Kpsi, ofgreater than or equal to 435 Kpsi, or of greater than or equal to 445Kpsi. In some embodiments, preferable ranges for Young's Modulus arebetween 420-480 Kpsi, between 435-465 Kpsi, and between 445-455 Kpsi. Ifthe Young's Modulus is too high, the film may not allow sufficientstretching prior to breaking. If the Young's Modulus is too low, thefilm may not have sufficient strength for balloon purposes.

The following examples are being submitted to further define variousspecies of the present disclosure. These examples are intended to beillustrative only and are not intended to limit the scope of the presentdisclosure. Also, parts and percentages are by weight unless otherwiseindicated.

EXAMPLES

This invention will be better understood with reference to the followingexamples, which are intended to illustrate specific embodiments withinthe overall scope of the invention.

Testing Methods

The oxygen barrier was measured on a MOCON Ox-Tran L series deviceutilizing ASTM D3985. Testing conditions used were 73° F., 0% relativehumidity, and 1 ATM. For this type of measurement, the gas barriersurface of the web is protected with a Stamark lamination. Thelamination protects the gas barrier surface from handling damage, butmakes no significant contribution to the oxygen barrier.

Dry bonding strength of the gas barrier layer (C) was measured byheat-sealing of a Dow PRIMACOR 3300 film to the metal surface on aSentinel heat sealer in a room which is air-conditioned at 73° F.+/−4°F. and 50%+/−5% RH. On the back side of the film, adhesive tape (3M 610)is applied to keep the film from breaking during the test. Heat sealconditions are 220° F. temperature, 20 seconds dwell time, and 40 psijaw pressure, 1 heated jaw. Prior to peeling the sealed materials arecut so that each web can be gripped in a separate jaw of the tensiletester and 1″×1″ section of sealed material can be peeled. The peel isinitiated by hand and then the two webs are pealed apart on an Instrontensile tester in a 180° configuration toward the PRIMACOR film. If themetal is separated from the substrate and remains attached to thePRIMACOR film then the mean force of the peel is reported as the metalbond strength.

The wet bonding strength of the gas barrier layer (C) was measured bythe same procedure as dry bonding strength, with the exception that acotton swab soaked with water is used to apply water to the interface ofthe sealed area as it is being peeled.

Sealing strength of the balloon was measured as follows. The seal layeris sealed to itself using a Pack Rite heat sealer with 15″×⅜″ jaw. Theheat seal conditions are 405° F. temperature, 2 seconds dwell time, and90 psi jaw pressure, 1 heated jaw. Prior to peeling, the sealedmaterials are cut so that each web can be gripped in a separate jaw ofthe tensile tester and a 1″×⅜″ section of sealed material can be peeled.The two webs are pealed apart on an Instron tensile tester in a 90°configuration known as a T-peel. The peel is initiated at a speed of2″/minute until 0.5 lbs of resistance is measured to preload the sample.Then the peel is continued at a speed of 6″/minute until the load dropsby 20%, signaling failure. The maximum recorded load prior to failure isreported as the seal strength.

Metal Optical Density is measured using a Gretag D200-II measurementdevice. The device is zeroed by taking a measurement without a sample inplace. Then the optical density of the polyester film layers andmetallic gas barrier layer is measured every 3″ across the web and theaverage is reported as the metal OD.

The melting point of the polyester resin is measured using a TAInstruments Differential Scanning calorimeter 2920. An 0.007 g resinsample is tested, using ASTM D3418-03 The preliminary thermal cycle isnot used, consistent with Note 6 of the ASTM Standard. The sample isthen heated up to 280° C. temperature at a rate of 10° C.temperature/minute, then cooled back to room temperature while heat flowand temperature data are recorded. The melting point is reported as thetemperature at the endothermic peak located between the range of 150 to280° C. temperature.

Haze and total light transmittance were measured using a Byk GardnerHaze Gard Plus Hazemeter according to ASTM D1003.

60 degree gloss was measured using a Byk Gardner Trigloss meteraccording to ASTM D523.

Floating time of the balloon is determined by inflating it with heliumgas and measuring the number of days that the balloon remains fullyinflated. A balloon is filled from a helium source using a pressureregulated nozzle designed for “foil” balloons, such as the ConwinPrecision Plus balloon inflation regulator and nozzle. The pressureshould be regulated to 16 inches of water column. The balloon should befilled with helium in ambient conditions of about 20° C. temperature and1 atmosphere barometric pressure. The balloon should be secured usingadhesive tape on the outside of the balloon below the balloon's valveaccess hole to avoid creating any slow leaks of helium gas through thevalve. During the testing, the balloon should be kept in a stableenvironment close to the ambient conditions stated. Changes intemperature and barometric pressure should be recorded to interpretfloat time results, as any major fluctuations can invalidate the test.The balloon is judged to be no longer fully inflated when the appearanceof the balloon changes so that the wrinkles running through the heatseal seam area become deeper and longer, extending into the front faceof the balloon, and the cross-section of the seam becomes a v-shape, asopposed to the rounded shape that characterizes a fully inflatedballoon. At this time, the balloon will still physically float, but willno longer have an aesthetically pleasing appearance. The number of daysbetween initial inflation and the loss of aesthetic appearance describedabove is reported as the floating time of the balloon.

Tensile properties: tensile strength at break, Young's Modulus, andElongation % of the films were measured substantially in accordance withASTM D882.

Example 1

A 36Ga polyester laminated film was prepared from a blend of highcrystalline polyester resin laminated to a layer of non-crystallinecopolyester tentered to a final stretch ratio of about 3.8″×3.8″. Thefilm was subsequently plasma treated and vacuum metallized with aluminumto an optical density of about 2.8″. Oxygen barrier measurements weremade on the top of the roll and at the bottom of the roll materials.Excellent barrier properties at the top and bottom of the roll weredetermined, showing good roll uniformity in the process. Furthermore,the film was processed into a final balloon form and the progress of thematerials was recorded via a barrier measurement. As shown in Table 1,the balloon fabrication process did not change the barrier properties ofthe film significantly through the entire process showing excellentstress crack resistance of the materials.

Comparative Example 1

A 40Ga metallized nylon sample was processed through the same balloonconverting steps. Before the converting process, the barrier of the thingauge metalized nylon web was measured. After final fabrication, thebarrier of the structure was also measured as shown in Table 1. Alsoshown in Table 1 are the actual hang times that the balloon fabricatedfrom the film retained its original shape, form and firmness.

Barrier results are shown in Table 1. The film described herein inembodiments maintains excellent barrier properties after processing intoballoon shapes, etc., and inflated. Comparatively, materials preparedfrom Nylon film show a significant degradation of barrier propertiesafter being processed and inflated.

TABLE 1 O₂ TR Barrier Testing (73° F., 0% RH) Hang time in SampleDescription cc/100 sqin/day days Example #1-Roll surface .02-.06 Example#1-Bottom of roll .02-.06 Example #1-Extrusion Coated Roll#1 .04-.09Example #1-Printed Roll#1 (ink area) .04-.09 Example #1-Printed Roll#1(clear area) .04-.09 Example #1-Slit and Printed process .04-.09 BalloonFabrication Roll#1 .04-.09 21+ Folded and Packaged Balloon .04-.09 21+Finished Roll#1 Comparative Example 1-Metallized Nylon .05-.09Comparative Example 1 After Balloon .05-.09 4-7 Fabrication ComparativeExample 1-after folding and .06-.22 2-7 insertion into package

Example 2

Polyester pellets as listed in Table 2 were mixed according to the blendratios shown in Table 3 and extruded using a vent-type two-screwextruder and filtered for the skin layer (b). Polyester pellets listedin Table 2 were mixed according to the blend ratio shown in Table 3,dried and then extruded via an extruder and filtered for the core layer(a). These melt streams were fed through a rectangular joining zone andlaminated into a two layer co-extruded (a)/(b) structure. The resultingcurtain was quenched on a casting drum, and oriented in the machinedirection with a roller stretcher at the stretching ratio of 4.8 timesat 250° F. Subsequently, using a chain driven stretcher, the film wasoriented in the transverse direction at the stretching ratio of 4.2times at 240° F. and heat-set at 460° F. The film was then wound up as abiaxially oriented polyester film (A) with the thickness listed in Table3. The surface of the core layer (a) was metallized with Al to anoptical density as listed in Table 4 and then wound up as a metallizedfilm. In the metallizing chamber, a Cu seeding was performed before theAl metallization to enhance the metal bond. The contamination of the Cuwas about 15 ng/cm² according to atomic absorption spectrometry.

The non-metallized surface of the metallized film was corona treated andwas coated with anchor coating (E) solution (Mica A-131-X) using gravurecoater. The anchor (E) was dried in a convective dryer. The dried anchorsurface was then extrusion coated with LLDPE sealant (B) (Dowlex 3010,13.6 μm thick).

The extrusion coated film was printed on the barrier surface with up to10 colors of ink, using a flexographic printing press. After printapplication, the inks were fully dried in a roller convective oven toremove solvents from the ink. The printed web was cut to lengthsadequate for the balloon fabrication process by rewinding on a centerdriven rewinder/slitter using lay-on nip rolls to control air entrapmentof the rewound roll.

The slit webs were fabricated into balloons by aligning 2 or more websinto position so that the printed graphics were properly registered toeach other, then adhered to each other by heat sealing (about 400° F.and 1 second) and cut into circle shape (17″ diameter). The seam of theballoons was ⅛″. A valve, as described in U.S. Pat. No. 4,917,646 wasinserted into an opening and the layers abutting the valve adhered toform a complete structure. The fabricated balloons may be mechanicallyfolded along multiple axes using mechanical processes or by hand forshipping. A certain number of balloons were taken for floating timetests as previously described. The properties of the films, webs andballoons are summarized in Table 4. The balloons of this Example 2showed extra long life lasting 30-35 days.

Example 3

The same materials and processes as described in Example 2 were used,except a plasma treatment was performed before the Al metallizationinstead of Cu seeding. The energy density of the treatment wasapproximately 1 KJ/M² and a nitrogen gas was used.

The properties of the films, webs and balloons are summarized in Table4. The balloons of this Example 3 showed extra long life, lasting 20-30days.

Example 4

The same materials and processes as described in Example 3 were used,except another Al metallizing was applied on the 1^(st) Al metallizinglayer using the same metallizing condition of the 1^(st) Al metallizing.

The properties of the films, webs and balloons are summarized in Table4. The metal bond strength test was done twice because the 2^(nd) Allayer had very poor bonding strength compared with the 1^(st) Al layer.The balloons of this Example 4 showed extra long life lasting about 30to 35 days.

Example 5

The same materials and processes as described in Example 3 were used,except a different optical density for the Al coating was used. Theproperties of the films, webs and balloons are summarized in Table 4.The balloons of this Example 5 showed marginal long life, of about 20days.

Example 6

The same materials and processes as described in Example 3 were used,except a different blend of the skin layer (b) was used.

The properties of the films, webs and balloons are summarized in Table4. The balloons of this Example 6 showed marginal long life, of about 20days.

Example 7

The same materials and processes as described in Example 3 were used,except the thickness of the Polyester film (A) was 12 μm.

The properties of the films, webs and balloons are summarized in Table4. The balloons of this Example 6 did show extra long life, lastingabout 20 days at low elevations such as sea level, where air density ishigh. However, typically sized balloons, such as those made from two 18inch panels, did not display a strong buoyant force at high elevationsdue to the low density of air and increased weight of the balloon.

Comparative Example 2

Polyester pellets listed in Table 2 were mixed according to the blendratio shown in Table 3, dried, extruded via an extruder, and filteredfor the single core layer (a). The resulting curtain was quenched on acasting drum, and oriented in the machine direction with a rollerstretcher at a stretching ratio of 4.8 times at 250° F. The resultingfilm was dried and oriented in the transverse direction as a stretchingratio of 4.2 times at 240° F., heat-set at 460° F., and then wound up asa biaxially oriented polyester film (A) with the thickness listed inTable 3.

One side of the biaxially oriented film was then metallized with Al toan optical density as listed in Table 3 and then wound as metallizedfilm. In the metallizing chamber, a plasma treatment process was used toenhance the metal bond. The energy density of the treatment wasapproximately 1 KJ/M² and a nitrogen gas was used. The followingprocesses were done the same as in Example 2. The properties of thefilms, webs and balloons are summarized in Table 4. The balloons of thisComp. Example 2 did not show extra long life, lasting less than 7 days.

Comparative Example 3

The same materials and processes as described in Example 3 were used,except no plasma treatment was applied.

The properties of the films, webs and balloons are summarized in Table4. The balloons of this Comp. Example 3 did not show extra long life,lasting less than 14 days.

Comparative Example 4

The same materials and processes as described in Example 3 were used,except the thickness of the Polyester film (A) was 15 μm.

The properties of the films, webs and balloons are summarized in Table4. The balloons of this Comp. Example 4 did not show extra long life,lasting less than 14 days. Typically sized balloons, such as those madefrom two 18 inch panels, did not display a strong buoyant force due tothe low density of air and increased weight of the balloon.

Comparative Example 5

A commercially available 40Ga (10 μm) nylon film (Biaxis BOPA) wasmetallized with Al and processed through the same materials as theprocesses. The properties of the films, webs and balloons are summarizedin Table 4. The balloons of this Comp. Example 5 showed short life lessthan 7 days.

TABLE 2 Melting point Particle Pellet Polyester IV degree C. Type ShapeSize Content a Polyethyleneterephthalate 0.65 about 260 No particle bPolyethyleneterephthalate 0.65 about 260 Silica Agglomerated 2.6 μm 3%(Average) c Kosa 8906C 0.65 about 209 No particle Copolyester ofisophtalic acid (about 18 mol %) and terephthalic acid (about 82 mol)

TABLE 3 Example 2 to 5, Comp. 3 6 7 Comp. 2, Comp. 6 Comp. 4 Structure(a)/(b) (a)/(b) (a)/(b) (a) (a)/(b) Core layer (a) Blend/% Pellet a 97Pellet a 97 Pellet a 97 Pellet a 97 Pellet a 97 Pellet b 3 Pellet b 3Pellet b 3 Pellet b 3 Pellet b 3 Thickness/μm 8.5 8.5 11.5 9 14.5 Skinlayer (b) Blend/% Pellet c 100 Pellet c 95 Pellet c 100 Pellet c 100Pellet b 5 Thickness/μm 0.5 0.5 0.5 0.5 Total thickness/μm 9 9 12 9 15

TABLE 4 Example 2 Example 3 Example 4 Example 5 Example 6 Gas barrierlayer(s) (C) Metal/Ceramic Al Al Al/Al Al Al Barrier Layer Metal OD 2.82.8 >3.5 1.6 2.8 Dry Bonding Strength >700 400 5/400 400 400 (g/in) WetBonding Strength >30 3 1/3  2 3 (g/in) O2TR (cc/100 sqin/day, 0.02-0.050.02-0.07 0.01-0.03 0.05-0.09 0.02-0.07 73 F., 0% RH) Sealing Strength4.5 Kgf/in 4.5 Kgf/in 4.5 Kgf/in 4.5 Kgf/in 4 Kgf/in Floating time(days) 30-35 20-30 30-35 about 20 about 20 Comp. Comp. Comp. Comp.Example 7 Example 2 Example 3 Example 4 Example 5 Gas barrier layer(s)(C) Metal/Ceramic Al Al Al Al Al Barrier Layer Metal OD 2.8 2.8 2.8 2.82.5 Dry Bonding Strength 400 400 100 400 250 (g/in) Wet Bonding Strength3 3 1 3 3 (g/in) O2TR (cc/100 sqin/day, 0.02-0.09 0.02-0.07 0.02-0.070.02-0.09 0.02-0.09 73 F., 0% RH) Sealing Strength 4.5 Kgf/in 2 Kgf/in4.5 Kgf/in 4.5 Kgf/in 4.5 Kgf/in Floating time (days) about 20 <7 <14<14 3-7

Examples Including Two Gas Barrier Layers Example 8

Polyester pellets as listed in Table 2 were mixed according to the blendratio shown in Table 5 and extruded using a vent-type two-screw extruderand filtered for the skin layer (b). Polyester pellets listed in Table 2were also mixed according to the blend ratio shown in Table 5, dried andthen extruded via extruder and filtered for the core layer (a). Thesemelt streams were fed through a rectangular joining zone and laminatedinto a two layer co-extruded (a)/(b) structure. The resulting curtainwas quenched on a casting drum, and oriented in the machine directionwith a roller stretcher at a stretching ratio of 4.8 times at 250° F.The core layer (a) side of this resulting film was coated with the waterbase primer (D) in Table 5 by in-line coating. Subsequently, using achain driven stretcher, the film was oriented in the transversedirection at the stretching ratio of 4.2 times at 240° F., heat-set at460° F., and then wound up as a biaxially oriented polyester film (A)with the thickness listed in Table 5. The surface of the core layer (a)was then metallized with Al to the optical density listed in Table 6 andthen wound up as a metallized film. Plasma treatment was done before theAl metallization. The Energy density of the treatment was approximately1 KJ/M² and a nitrogen gas was used.

The non-metallized surface of the metallized film was corona treated andwas coated with anchor coating (E) solution (Mica A-131-X) using gravurecoater. The anchor (E) was dried in a convective dryer. The dried anchorsurface was then coated with LLDPE sealant (B) (Dowlex 3010, 13.6 μmthick) by an extrusion coating method.

The barrier surface of the extrusion coated film was then printed onwith up to 10 colors of ink, using a flexographic printing press. Afterthe print application, the inks were fully dried in a roller convectiveoven to remove solvents from the ink. The printed web was cut to lengthsadequate for the balloon fabrication process by rewinding on a centerdriven rewinder/slitter using lay-on nip rolls to control air entrapmentof the rewound roll. The slit webs were fabricated into balloons byaligning 2 or more webs into position so that the printed graphics wereproperly registered to each other, then adhered to each other by heatsealing (at about 400° F. for 1 second) and cut into a circle shape (17″diameter). The seam of the balloons was ⅛″. A valve, as described inU.S. Pat. No. 4,917,646, was inserted into an opening and the layersabutting the valve adhered to form a complete structure. The fabricatedballoons were mechanically folded along multiple axes using a mechanicalprocess or by hand for shipping. A certain number of balloons were takenfor floating time testing as previously described. The properties of thefilms, webs and balloons are summarized in Table 6. The balloons of thisExample 8 showed an extra extra long life lasting more than 50 days.

Example 9

The same materials and processes as described in Example 8 were used,except a different gas barrier polymer for the gas barrier layer (D) wasused.

The properties of the films, webs and balloons are summarized in Table6. The balloons of this example showed extra extra long life, lastingmore than 50 days.

Example 10

The same materials and processes as described in Example 8 were used,except a different gas barrier polymer for the gas barrier layer (D) wasused.

The properties of the films, webs and balloons are summarized in Table6. The balloons of this example showed extra extra long life, lastingabout 50 days.

Example 11

Polyester pellets as listed in Table 2 were mixed according to the blendratio shown in Table 5 and extruded using a vent-type two-screw extruderand filtered for the skin layer (b). Polyester pellets listed in Table 2were mixed according to the blend ratio shown in Table 5, dried, andthen extruded via an extruder and filtered for the core layer (a). Thesemelt streams were fed through a rectangular joining zone and laminatedinto a two layer co-extruded (a)/(b) structure. The resulting curtainwas quenched on a casting drum, and oriented in the machine directionwith a roller stretcher at a stretching ratio of 4.8 times at 250° F.Subsequently, using a chain driven stretcher, the film was oriented inthe transverse direction at a stretching ratio of 4.2 times at 240° F.,heat-set at 460° F., and then wound up as biaxially oriented polyesterfilm (A) with the thickness listed in Table 5. The surface of the corelayer (a) was metallized with Al to the optical density listed in Table6 and then wound up as a metallized film. Plasma treatment was donebefore the Al metallization. The energy density of the treatment wasapproximately 1 KJ/M² and a nitrogen gas was used.

The metallized surface of the metallized film was coated with a watersolution of EVOH co-polymer with vinyl acetate (Kuraray “EXCEVAL”AQ4105) as the polymeric barrier layer (D) by a conventional gravurecoater and dried in a convective dryer. The dry thickness of the barrierlayer (D) was about 0.3 μm.

The following processes were done the same as in Example 8. Theproperties of the films, webs and balloons are summarized in Table 6.The balloons of this Example 8 showed extra extra long life lasting40-50 days.

Examples of Long Life Clear/Translucent Balloon Example 12

Polyester pellets as listed in Table 2 were mixed according to the blendratio shown in Table 5 and extruded using a vent-type two-screw extruderand filtered for the skin layer (b). Polyester pellets listed in Table 2were also mixed according to the blend ratio shown in Table 5, dried andthen extruded via an extruder and filtered for the core layer (a). Thesemelt streams were fed through a rectangular joining zone and laminatedinto a two layer co-extruded (a)/(b) structure. The resulting curtainwas quenched on a casting drum, and oriented in the machine directionwith a roller stretcher at a stretching ratio of 4.8 times at 250° F.Subsequently, using a chain driven stretcher, the film was oriented inthe transverse direction at the stretching ratio of 4.2 times at 240°F., heat-set at 460° F., and then wound up as a biaxially orientedpolyester film (A) with the thickness listed in Table 5. The surface ofthe core layer (a) was then deposited with AlOx as the gas barrier layer(C) and then wound up as a clear gas barrier film. In the depositionchamber, a Cu seeding was performed before the AlOx deposition toenhance the bond. The contamination of the Cu was about 15 ng/cm²according to atomic absorption spectrometry.

The gas barrier layer (C) was coated with PVOH as the polymeric barrierlayer (D) by a conventional gravure coater and dried in a convectivedryer. The dry thickness of the barrier layer (D) was about 0.5 μm.

The non-barrier surface of the film was corona treated and was coatedwith anchor coating (E) solution (Mica A-131-X) using gravure coater.The anchor (E) was dried in a convective dryer. The dried anchor surfacewas then coated with LLDPE sealant (B) by an extrusion coating method ona matte surface chill roll. The following processes were done the sameas in Example 8. The properties of the films, webs and balloons aresummarized in Table 7. The balloons of this Example 8 showed extra longlife lasting more than 30 days.

Example 13

The same materials and processes as described in Example 12 were used,except a mirror surface chill roll are used instead of the matte surfacechill roll.

The properties of the films, webs and balloons are summarized in Table7. The balloons of this example showed extra long life, lasting about 30days.

Comparative Example 6

Polyester pellets listed in Table 2 were mixed according to the blendratio shown in Table 3, dried, extruded via an extruder, and filteredfor the single core layer (a). The resulting curtain was quenched on acasting drum, and oriented in the machine direction with a rollerstretcher at a stretching ratio of 4.8 times at 250° F. The resultingfilm was dried and oriented in the transverse direction at a stretchingratio of 4.2 times at 240° F., heat-set at 460° F., and then wound up asa biaxially oriented polyester film (A) with the thickness listed inTable 3.

The following processes were done the same as in Example 12. Theproperties of the films, webs and balloons are summarized in Table 7.The balloons of this Comp. Example 6 did not show extra long life,lasting less than 7 days.

Comparative Example 7

A commercially available 1 mil (23 μm) clear EVOH/Nylon extrusion film(Gunze 525 Heptax) was fabricated to the balloon. The properties of thefilms, webs and balloons are summarized in Table 7. The balloons of thisComp. Example 7 showed short life, less than 5 days.

TABLE 5 Example 8 9 10 11 12 and 13 Structure (a)/(b) (a)/(b) (a)/(b)(a)/(b) (a)/(b) Core layer (a) Blend/% Pellet a 97 Pellet a 97 Pellet a97 Pellet a 97 Pellet a 97 Pellet b 3 Pellet b 3 Pellet b 3 Pellet b 3Pellet b 3 Thickness/um 8.5 8.5 8.5 8.5 8.5 Skin layer (b) Blend/%Pellet c 100 Pellet c 100 Pellet c 100 Pellet c 100 Pellet c 100Thickness/um 0.5 0.5 0.5 0.5 0.5 Gas barrier layer (D) Recipe D1 96 partD3 100 part D4 70 part D6 100 part PVOH 100 part D2  4 part D5 30 partSolid of solution/% 6 8 12 8 Dry thickness/um 0.05 0.05 0.05 0.3 0.5Total thickness/um 9 9 9 9.3 9.5 D1: Polyvinyl alcohol (about 90 mol%)-polyvinyl amine (about 10 mol %) copolymer D2: Epichlorohydrincross-linker D3: PVOH and cross-linker, commercially available as MicaR2462 from Mica Corp D4: EVOH, commercially available as EXCEVAL RS2117from Kuraray D5: PVOH, commercially available as Celvol 24-203 D6: EVOH,commercially available as EXCEVAL AQ4105 from Kuraray

TABLE 6 Example 8 Example 9 Example 10 Example 11 Gas Metal/ Al Al Al Albarrier Ceramic layer (C) Barrier Layer Metal 2.8 2.8 2.8 2.8 OD O2TR0.008 0.008 0.01 0.015 (cc/100 sqin/day, 73 F., 0% RH) Sealing 4.5Kgf/in 4.5 Kgf/in 4.5 Kgf/in 4.5 Kgf/in Strength Floating >50 >50 about50 40-50 time (days)

TABLE 7 Exam- Exam- ple 12 ple 13 Comp. 6 Comp. 7 Gas Metal/ AlOx AlOxAlOx EVOH barrier Ceramic layer (C) Barrier Layer Haze % 6 to 85 3 to 856 to 85 5 to 85 Total 35 to 95  35 to 95  35 to 95  35 to 92  lighttransmittance % Gloss at 60 to 120 60 to 120 60 to 120 60 to 120 60degree O2TR 0.01 0.01 0.01 0.03 (cc/100 sqin/day, 73 F., 0% RH) Sealing4.5 Kgf/in 4.5 Kgf/in 2 Kgf/in 4 Kgf/in Strength Floating >30 >30 <7about 5 time (days)

Examples of Elastic and Formable Balloons Example 14

A laminated film was prepared by co-extruding a core layer of highcrystalline polyester resin and a non-crystalline PET layer through arectangular joining zone to form a two layer co-extruded (a)/(b)structure. The core layer included crystalline PET, particles to provideroughness characteristics and recycle pellets and had a thickness of 8.5um. The non-crystalline layer was amorphous PET and had a thickness of0.5 um. The resulting curtain was quenched on a casting drum, andoriented in the machine direction at a stretching ratio of 4.8 times at246° F. with a roller stretcher. Subsequently, using a chain drivenstretcher, the film was oriented in the transverse direction at astretching ratio of 4.2 times at 240° F., heat-set at 460° F., and thenwound up as a biaxially oriented polyester film (A). Elongation (%),tensile strength, and Young's Modulus in the machine direction aresummarized in Table 9.

Example 15

Example 14 was repeated except the machine direction stretch temperaturewas increased to 260° F. This decreased the orientation of the corelayer in the machine direction. Elongation (%), tensile strength, andYoung's Modulus were then measured and the results are summarized inTable 9.

Example 16

Example 14 was repeated except the machine direction stretch reduced to4.5 times. This decreased the orientation of the core layer in themachine direction. Elongation (%), tensile strength, and Young's Moduluswere then measured and the results are summarized in Table 9.

TABLE 9 Machine Direction Total Machine Tensile Tensile Young's Young'sStretch Temperature Direction Elongation Strength Strength ModulusModulus Examples (° F.) Stretch Draw (%) (kg/mm²) (kpsi) (kg/mm²) (kpsi)14 246 4.8 108 29.7 42.2 517 735.3 15 260 4.8 141 21.6 30.7 430 611.6 16246 4.5 137 24.3 34.6 448 637.2

Elongation % v. Machine Direction Stretching (MDS) Temperature for thefilms of Examples 14 and 15 were plotted in FIG. 6. Elongation % v.Total MDS Draw for the films of Examples 14 and 16 were plotted in FIG.7. Tensile Strength v. MDS Temperature for the films of Examples 14 and15 were plotted in FIG. 8. Tensile Strength v. Total MDS Draw for thefilms of Examples 14 and 16 were plotted in FIG. 9. Young's Modulus v.MDS Temperature for the films of Examples 14 and 15 were plotted in FIG.10. Young's Modulus v. Total MDS Draw for the films of Examples 14 and16 were plotted in FIG. 11. Examples 14-16 and FIGS. 6 and 7 show thatby stretching the film at a higher temperature or by reducing theoverall stretch (draw) the film becomes less oriented, and thereforefilm Elongation (before break) becomes higher, while tensile strengthand Young's Modulus become lower. The change in these properties allowsthe film to stretch more before breaking as the film becomes lessorientated. This means that a finished balloon formed from the polyesterfilm can unexpectedly be stretched instead of bursting whenoverinflated.

This application discloses several numerical ranges in the text andfigures. The numerical ranges disclosed are intended to support anyrange or value within the disclosed numerical ranges even though aprecise range limitation is not stated verbatim in the specificationbecause this invention can be practiced throughout the disclosednumerical ranges. It is also to be understood that all numerical valuesand ranges set forth in this application are necessarily approximate.

The above description is presented to enable a person skilled in the artto make and use the invention, and is provided in the context of aparticular application and its requirements. Various modifications tothe preferred embodiments will be readily apparent to those skilled inthe art, and the generic principles defined herein may be applied toother embodiments and applications without departing from the spirit andscope of the invention. Thus, this invention is not intended to belimited to the embodiments shown, but is to be accorded the widest scopeconsistent with the principles and features disclosed herein. Finally,the entire disclosure of the patents and publications referred in thisapplication are hereby incorporated herein by reference.

1. A balloon formed from a lamination, the lamination comprising; apolyester film with a total thickness of 4 μm to 12 μm comprising abiaxially oriented polyester core layer and at least one amorphouscopolyester skin layer, wherein the polyester film has an Elongation %in the transverse direction (TD) or machine direction (MD) of greaterthan 125%.
 2. The balloon of claim 1, wherein the polyester film has atensile strength of 30-40 KPsi in the TD or MD direction.
 3. The balloonof claim 1, wherein the polyester film has a Young's Modulus of 420-480KPsi in the TD or MD direction.
 4. The balloon of claim 1, wherein thepolyester film has an Elongation % in the transverse direction (TD) andmachine direction (MD) of greater than 125%.
 5. The balloon of claim 1,wherein the lamination further comprises: a sealant layer adjacent tothe amorphous copolyester skin layer; and a gas barrier layer on anopposite side of the polyester film from the sealant layer, wherein anoxygen transmission rate of the balloon is less than 0.1 cc/100sqin/day, a dry bonding strength of the gas barrier layer to the surfaceof the polyester film is more than 300 g/in, a sealing strength of theballoon is more than 3.5 kg/in, and a floating time of the balloon ismore than 20 days.
 6. The balloon of claim 5, wherein the gas barrierlayer is a metal or ceramic layer.
 7. The balloon of claim 5, whereinthe sealant layer comprises a low density polyethylene.
 8. The balloonof claim 5, wherein the lamination further comprises an anchor layerbetween the sealant layer and the amorphous copolyester skin layer. 9.The balloon of claim 5, wherein the lamination further comprises aprimer layer between the biaxially oriented core layer and the gasbarrier layer.
 10. The balloon of claim 1, wherein the core layer isco-extruded with the amorphous copolyester skin layer.
 11. The balloonof claim 1, wherein the amorphous copolyester skin layer has a meltingpoint of less than 210° C.
 12. The balloon of claim 1 wherein, theamorphous copolyester skin layer contains no added particles.
 13. Theballoon of claim 5, wherein the dry bonding strength of the gas barrierlayer is more than 600 g/in.
 14. A method of forming a formable ballooncomprising: placing a balloon in a mold, wherein the balloon is formedfrom a lamination and the lamination comprises a polyester filmcomprising a biaxially oriented polyester core layer and at least oneamorphous copolyester skin layer, the polyester film has a totalthickness of 4 μm to 12 μm, and the polyester film has an Elongation %in the transverse direction (TD) or machine direction (MD) of greaterthan 125%; and inflating the balloon in the mold to form the balloon toa shape of the mold.
 15. The method of claim 14, wherein the polyesterfilm has an Elongation % in the transverse direction (TD) and machinedirection (MD) of greater than 125%.
 16. The method of claim 14, whereinthe polyester film has a tensile strength of 30-40 KPsi in the TD or MDdirection.
 17. The method of claim 14, wherein the polyester film has aYoung's Modulus of 420-480 KPsi in the TD or MD direction.
 18. Themethod of claim 14, wherein the lamination further comprises: a sealantlayer adjacent to the amorphous copolyester skin layer; and a gasbarrier layer on an opposite side of the polyester film from the sealantlayer, wherein an oxygen transmission rate of the balloon is less than0.1 cc/100 sqin/day, a dry bonding strength of the gas barrier layer tothe surface of the polyester film is more than 300 g/in, a sealingstrength of the balloon is more than 3.5 kg/in, and a floating time ofthe balloon is more than 20 days.
 19. The method of claim 18, whereinthe gas barrier layer is a metal or ceramic layer.
 20. A deformableballoon formed from a lamination, the lamination comprising; a polyesterfilm with a total thickness of 4 μm to 12 μm comprising a biaxiallyoriented polyester core layer and at least one amorphous copolyesterskin layer, wherein the polyester film has an Elongation % in thetransverse direction (TD) or machine direction (MD) of greater than125%, and the balloon has a higher elongation and lower tensile strengthin the TD or MD direction.
 21. The deformable balloon of claim 20,wherein the polyester film has a tensile strength of 30-40 KPsi in theTD or MD direction.
 22. The deformable balloon of claim 20, wherein thepolyester film has a Young's Modulus of 420-480 KPsi in the TD or MDdirection.
 23. The deformable balloon of claim 20, wherein thelamination further comprises: a sealant layer adjacent to the amorphouscopolyester skin layer; and a gas barrier layer on an opposite side ofthe polyester film from the sealant layer, wherein an oxygentransmission rate of the balloon is less than 0.1 cc/100 sqin/day, a drybonding strength of the gas barrier layer to the surface of thepolyester film is more than 300 g/in, a sealing strength of the balloonis more than 3.5 kg/in, and a floating time of the balloon is more than20 days.
 24. The deformable balloon of claim 23, wherein the gas barrierlayer is a metal or ceramic layer.
 25. A method of forming a balloonfrom a lamination comprising: co-extruding a polyester film comprising apolyester core layer comprising crystalline polyester and at least oneamorphous copolyester skin layer; and biaxially orienting the core layerunder conditions such that the polyester film has an Elongation % in thetransverse direction (TD) or machine direction (MD) of greater than125%.
 26. The method of claim 25, wherein the polyester film has anElongation % in the transverse direction (TD) and machine direction (MD)of greater than 125%.
 27. The method of claim 25, wherein the polyesterfilm has a tensile strength of 30-40 KPsi in the TD or MD direction. 28.The method of claim 25, wherein the polyester film has a Young's Modulusof 420-480 KPsi in the TD or MD direction.
 29. The method of claim 25,further comprising: applying a sealant layer onto the amorphouscopolyester skin layer; and applying a gas barrier layer onto anopposite side of the polyester film from the sealant layer, wherein anoxygen transmission rate of the balloon is less than 0.1 cc/100sqin/day, a dry bonding strength of the gas barrier layer to the surfaceof the polyester film is more than 300 g/in, a sealing strength of theballoon is more than 3.5 kg/in, and a floating time of the balloon ismore than 20 days.
 30. The method of claim 28, wherein the gas barrierlayer is a metal or ceramic layer.